Bump flinkVersion from 1.19.1 to 1.20.0 (#52)

Bumps `flinkVersion` from 1.19.1 to 1.20.0.

Updates `org.apache.flink:flink-java` from 1.19.1 to 1.20.0
- [Commits](apache/flink@release-1.19.1...release-1.20.0)

Updates `org.apache.flink:flink-test-utils` from 1.19.1 to 1.20.0

---
updated-dependencies:
- dependency-name: org.apache.flink:flink-java
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: org.apache.flink:flink-test-utils
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

build.gradle.kts

@@ -17,7 +17,7 @@ repositories {
 dependencies {
     implementation(kotlin("reflect"))
 
-    val flinkVersion = "1.19.1"
+    val flinkVersion = "1.20.0"
     implementation("org.apache.flink:flink-java:$flinkVersion")
 
     testImplementation("org.apache.flink:flink-test-utils:$flinkVersion")